Syncope recurrence and mortality: a systematic review

Serious outcomes among emergency department patients with presyncope: A systematic review

BACKGROUND

Syncope is transient loss of consciousness, and in presyncope, patients experience same prodromal symptoms without losing consciousness. While studies have extensively reported the risk of serious outcome among emergency department (ED) syncope, the outcome for patients with presyncope and their management are not well studied. We undertook a systematic review to assess the occurrence/identification of short-term (30-day) serious outcomes among ED patients with presyncope.

METHODS

ED studies that enrolled patients with presyncope and reported any short-term serious outcome were included. Studies that enrolled patients without presyncope (e.g., hypoglycemia, seizure, and stroke) were excluded. We restricted our study to only English publications and searched the MEDLINE, Embase, Scopus, and Web of Science from the inception date to July 2023. We used SIGN 50 tool for assessment of risk of bias.

RESULTS

In total, 1788 articles were screened by two reviewers and 32 articles were selected for full-text assessment. Five (four prospective and one retrospective) studies with 2741 presyncope patients were included. Four studies were from North America and the fifth one was from Europe. Included studies had weaknesses due to risk of bias, but all had acceptable quality. The prevalence of overall adverse outcome varied 4.4%-26.8% for all adults and 5.5%-18.7% among older patients; arrhythmia was the most prevalent (17.4% in one study), followed by anemia/hemorrhage as reported in different studies. Among older patients, myocardial infarction was the third most common serious outcome reported in one study.

CONCLUSIONS

The prevalence of short-term serious outcomes varies from 4% to 27% among ED patients with presyncope in our review, with arrhythmia being the most common serious outcome. Our review indicates that presyncope may carry a similar risk to syncope, and hence, the same level of caution should be exercised for ED presyncope management as syncope.

Role of Artificial Intelligence in Improving Syncope Management

Syncope is common in the general population and is a common presenting symptom in acute care settings. Substantial costs are attributed to care of patients with syncope. Current challenges include differentiating syncope from its mimickers, identifying serious underlying conditions that caused the syncope, and wide variations in current management. While validated risk tools exist especially for short-term prognosis, there is inconsistent application, and the current approach does not meet the patient needs/expectations. Artificial intelligence (AI) techniques such as machine learning methods including natural language processing can potentially address the current challenges in syncope management. Preliminary evidence from published studies indicates that it is possible to accurately differentiate syncope from its mimickers and predict short-term prognosis/ hospitalization. More recently AI analysis of ECG has shown promise in detection of serious structural and functional cardiac abnormalities which has the potential to improve syncope care. Future AI studies have the potential to address current issues in syncope management. AI can automatically prognosticate risk in real time by accessing traditional and non-traditional data. However, steps to mitigate known problems such generalizability, patient privacy, data protection, and liability will be needed. In the past AI has had limited impact due to underdeveloped analytical methods, lack of computing power, poor access to powerful computing systems, and availability of reliable high-quality data. All impediments except data have been solved. AI will live up to its promise to transform syncope care if the health care system can satisfy AI requirement of large scale, robust, accurate, and reliable data.

Syncope and Traffic Crash: A Population-Based Case-Crossover Analysis

BACKGROUND

Among individuals with recent syncope, recurrence of syncope while driving might incapacitate a driver and cause a motor vehicle crash. Current driving restrictions assume that some forms of syncope transiently increase crash risk. We evaluated whether syncope is associated with a transient increase in crash risk.

METHODS

We performed a case-crossover analysis of linked administrative health and driving data from British Columbia, Canada (2010 to 2015). We included licensed drivers who visited an emergency department with "syncope and collapse" and who were involved as a driver in an eligible motor vehicle crash, both within the study interval. Using conditional logistic regression, we compared the rate of emergency visits for syncope in the 28 days before crash (the "pre-crash interval") with the rate of emergency visits for syncope in 3 self-matched 28-day control intervals (ending 6, 12, and 18 months before the crash).

RESULTS

Among eligible crash-involved drivers, 47 of 3026 pre-crash intervals and 112 of 9078 control intervals had emergency visits for syncope, indicating syncope was not significantly associated with subsequent crash (1.6% vs 1.2%; adjusted odds ratio [OR], 1.27; 95% confidence interval [CI], 0.90-1.79; P = 0.18). There was no significant association between syncope and crash in subgroups at higher risk for adverse outcomes after syncope (eg, age > 65 years, cardiovascular disease, cardiac syncope).

CONCLUSIONS

In the context of prevailing modifications of driving behaviour after syncope, an emergency department visit for syncope did not transiently increase the risk of subsequent traffic collision. Overall crash risks after syncope appear to be adequately addressed by current driving restrictions.

New-onset syncope in diabetic patients treated with sodium-glucose cotransporter-2 inhibitors versus dipeptidyl peptidase-4 inhibitors: a Chinese population-based cohort study

BACKGROUND AND AIMS

Syncope is a symptom that poses an important diagnostic and therapeutic challenge, and generates significant cost for the healthcare system. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have demonstrated beneficial cardiovascular effects, but their possible effects on incident syncope have not been fully investigated. This study compared the effects of SGLT2i and dipeptidyl peptidase-4 inhibitors (DPP4i) on new-onset syncope.

METHODS AND RESULTS

This was a retrospective, territory-wide cohort study enrolling type 2 diabetes mellitus (T2DM) patients treated with SGLT2i or DPP4i between 1 January 2015 and 31 December 2020, in Hong Kong, China. The outcomes were hospitalization of new-onset syncope, cardiovascular mortality, and all-cause mortality. Multivariable Cox regression and different approaches using the propensity score were applied to evaluate the association between SGLT2i and DPP4i with incident syncope and mortality. After matching, a total of 37 502 patients with T2DM were included (18 751 SGLT2i users vs. 18 751 DPP4i users). During a median follow-up of 5.56 years, 907 patients were hospitalized for new-onset syncope (2.41%), and 2346 patients died from any cause (6.26%), among which 471 deaths (1.26%) were associated with cardiovascular causes. Compared with DPP4i users, SGLT2i therapy was associated with a 51% lower risk of new-onset syncope [HR 0.49; 95% confidence interval (CI) 0.41-0.57; P < 0.001], 65% lower risk of cardiovascular mortality (HR 0.35; 95% CI 0.26-0.46; P < 0.001), and a 70% lower risk of all-cause mortality (HR 0.30; 95% CI 0.26-0.34; P < 0.001) in the fully adjusted model. Similar associations with syncope were observed for dapagliflozin (HR 0.70; 95% CI 0.58-0.85; P < 0.001), canagliflozin (HR 0.48; 95% CI 0.36-0.63; P < 0.001), and ertugliflozin (HR 0.45; 95% CI 0.30-0.68; P < 0.001), but were attenuated for empagliflozin (HR 0.79; 95% CI 0.59-1.05; P = 0.100) after adjusting for potential confounders. The subgroup analyses suggested that, compared with DPP4i, SGLT2i was associated with a significantly decreased risk of incident syncope among T2DM patients, regardless of gender, age, glucose control status, Charlson comorbidity index, and the association remained constant amongst those with common cardiovascular drugs and most antidiabetic drugs at baseline.

CONCLUSION

Compared with DPP4i, SGLT2i was associated with a significantly lower risk of new-onset syncope in patients with T2DM, regardless of gender, age, degree of glycaemic control, and comorbidity burden.

Twenty-five years of research on syncope

Over the last 25 years, the Europace journal has greatly contributed to dissemination of research and knowledge in the field of syncope. More than 400 manuscripts have been published in the journal. They undoubtedly improved our understanding of syncope. This symptom is now clearly differentiated from other forms of transient loss of consciousness. The critical role of vasodepression and/or cardioinhibition as final mechanisms of reflex syncope is emphasized. Current diagnostic approach sharply separates between cardiac and autonomic pathways. Physiologic insights have been translated, through rigorously designed clinical trials, into non-pharmacological or pharmacological interventions and interventional therapies. The following manuscript is intended to give the reader the current state of the art of knowledge of syncope by highlighting landmark contributions of the Europace journal.

Syncope with autonomic dysfunction assessed with the Thai-COMPASS 31 questionnaire

Introduction

Alteration of autonomic function is the main pathophysiology of most types of syncope, including syncope due to orthostatic hypotension and neurally mediated syncope or reflex syncope. The aim of this study was to investigate the difference in autonomic dysfunction assessed between each type of syncope and to evaluate the association between the severity of autonomic dysfunction and the recurrence of syncope.

Methodology

Three hundred and six participants, including 195 syncope and 109 healthy control participants, were recruited to this retrospective cohort study. Autonomic function was initially assessed by the Thai version of the Composite Autonomic Symptom Score 31 (COMPASS 31), a self-administered questionnaire.

Result

According to one hundred and ninety-five syncope participants, twenty-three participants had syncope due to orthostatic hypotension, 61 had reflex syncope, 79 had presyncope, and 32 had unclassified syncope. Participants in the syncope due to orthostatic hypotension and reflex syncope groups had significantly higher COMPASS 31 scores than the control and presyncope groups, of which the syncope due to orthostatic hypotension group had the highest score. The cutoff score of 32.9 for COMPASS 31 had a sensitivity of 50.0% and a specificity of 81.9% to predict the recurrence of syncope.

Conclusion

The degree of autonomic dysfunction, which was assessed by COMPASS 31, could vary depending on the syncope type. The COMPASS 31, which is an easy-to-use self-administered questionnaire utilized for the assessment of autonomic symptoms and function, was a helpful tool for classifying some types of syncope and predicting the recurrence of syncope, which could lead to appropriate further management.

Vasovagal Syncope at Work: A Narrative Review for an Occupational Management Proposal

Syncope is a complex clinical manifestation that presents considerable diagnostic difficulties and, consequently, numerous critical issues regarding fitness for work, especially for high-risk tasks. To date, it is impossible to quantify the exact impact of syncope on work and public safety since it is highly improbable to identify loss of consciousness as the fundamental cause of work or driving-related accidents, especially fatal injuries. Working at high-risk jobs such as public transport operators, in high elevations, or with exposure to moving parts, construction equipment, fireworks, or explosives demand attention and total awareness. Currently, no validated criteria or indicators are available for occupational risk stratification of a patient with reflex syncope to return to work. By drawing inspiration from the updated literature, this narrative review intends to summarise the leading knowledge required regarding the return to work for subjects affected by syncope. According to the available data, the authors highlighted some key findings, summarised in macro-items, such as defined risk stratification for vasovagal accidents, return to work after a critical event, and a focus on pacemaker (PM) implementation. Lastly, the authors proposed a flowchart for occupational physicians to help them manage the cases of workers affected by syncope and exposed to levels of risk that could represent a danger to the workers' health.

Multicentre open label randomised controlled trial of immediate enhanced ambulatory ECG monitoring versus standard monitoring in acute unexplained syncope patients: the ASPIRED study

INTRODUCTION

Diagnosing underlying arrhythmia in emergency department (ED) syncope patients is difficult. There is a evidence that diagnostic yield for detecting underlying arrhythmia is highest when cardiac monitoring devices are applied early, ideally at the index visit. This strategy has the potential to change current syncope management from low diagnostic yield Holter to higher yield ambulatory monitoring, reduce episodes of syncope, reduce risk of recurrence and its potential serious consequences, reduce hospital admissions, reduce overall health costs and increase quality of life by allowing earlier diagnosis, treatment and exclusion of clinically important arrhythmias.

METHODS AND ANALYSES

This is a UK open prospective parallel group multicentre randomised controlled trial of an immediate 14-day ambulatory patch heart monitor vs standard care in 2234 patients presenting acutely with unexplained syncope. Our patient focused primary endpoint will be number of episodes of syncope at 1 year. Health economic evaluation will estimate the incremental cost per syncope episode avoided and quality-adjusted life year gained.

ETHICS AND DISSEMINATION

Informed consent for participation will be sought. The ASPIRED trial received a favourable ethical opinion from South East Scotland Research Ethics Committee 01 (21/SS/0073). Results will be disseminated via scientific publication, lay summary and visual abstract.

TRIAL REGISTRATION NUMBER

ISRCTN 10278811.

Syncope and subsequent traffic crash: A responsibility analysis

BACKGROUND

Physicians are often asked to counsel patients about driving safety after syncope, yet little empirical data guides such advice.

METHODS

We identified a population-based retrospective cohort of 9,507 individuals with a driver license who were discharged from any of six urban emergency departments (EDs) with a diagnosis of 'syncope and collapse'. We examined all police-reported crashes that involved a cohort member as a driver and occurred between 1 January 2010 and 31 December 2016. We categorized crash-involved drivers as 'responsible' or 'non-responsible' for their crash using detailed police-reported crash data and a validated responsibility scoring tool. We then used logistic regression to test the hypothesis that recent syncope was associated with driver responsibility for crash.

RESULTS

Over the 7-year study interval, cohort members were involved in 475 police-reported crashes: 210 drivers were deemed responsible and 133 drivers were deemed non-responsible for their crash; the 132 drivers deemed to have indeterminate responsibility were excluded from further analysis. An ED visit for syncope occurred in the three months leading up to crash in 11 crash-responsible drivers and in 5 crash-non-responsible drivers, suggesting that recent syncope was not associated with driver responsibility for crash (adjusted odds ratio, 1.31; 95%CI, 0.40-4.74; p = 0.67). However, all drivers with cardiac syncope were deemed responsible, precluding calculation of an odds ratio for this important subgroup.

CONCLUSIONS

Recent syncope was not significantly associated with driver responsibility for traffic crash. Clinicians and policymakers should consider these results when making fitness-to-drive recommendations after syncope.

Vasovagal Syncope during Office Hysteroscopy—A Frequently Overlooked Unpleasant Complication

Due to technological advancements in miniaturization of instruments and improved optics, the number of office hysteroscopic procedures has increased over time. Office hysteroscopy is preferred due to avoidance of general anesthesia and decreased overall cost. Vasovagal syncope has been implied as the most common complication. Vasovagal syncope is associated with inappropriate reflex vasodilation and bradycardia in the setting of an acute malfunction between the autonomic nervous system and the cardiovascular system; however, there is no mortality associated with vasovagal syncope. A management strategy for acute vasovagal reflex during office hysteroscopy is proposed in order to manage this common complication.

Syncope and the Risk of Subsequent Motor Vehicle Crash: A Population-Based Retrospective Cohort Study

IMPORTANCE

Medical driving restrictions are burdensome, yet syncope recurrence while driving can cause a motor vehicle crash (MVC). Few empirical data inform current driving restrictions after syncope.

OBJECTIVE

To examine MVC risk among patients visiting the emergency department (ED) after first-episode syncope.

DESIGN, SETTING, AND PARTICIPANTS

A population-based, retrospective observational cohort study of MVC risk after first-episode syncope was performed in British Columbia, Canada. Patients visiting any of 6 urban EDs for syncope and collapse were age- and sex-matched to 4 control patients visiting the same ED in the same month for a condition other than syncope. Patients' ED medical records were linked to administrative health records, driving history, and detailed crash reports. Crash-free survival among individuals with syncope was then compared with that among matched control patients. Data analyses were performed from May 2020 to March 2022.

EXPOSURES

Initial ED visit for syncope.

MAIN OUTCOMES AND MEASURES

Involvement as a driver in an MVC in the year following the index ED visit. Crashes were identified using insurance claim data and police crash reports.

RESULTS

The study cohort included 43 589 patients (9223 patients with syncope and 34 366 controls; median [IQR] age, 54 [35-72] years; 22 360 [51.3%] women; 5033 [11.5%] rural residents). At baseline, crude MVC incidence rates among both the syncope and control groups were higher than among the general population (12.2, 13.2, and 8.2 crashes per 100 driver-years, respectively). In the year following index ED visit, 846 first crashes occurred in the syncope group and 3457 first crashes occurred in the control group, indicating no significant difference in subsequent MVC risk (9.2% vs 10.1%; adjusted hazard ratio [aHR], 0.93; 95% CI, 0.87-1.01; P = .07). Subsequent crash risk among patients with syncope was not significantly increased in the first 30 days after index ED visit (aHR, 1.07; 95% CI, 0.84-1.36; P = .56) or among subgroups at higher risk of adverse events after syncope (eg, age >65 years; cardiogenic syncope; Canadian Syncope Risk Score ≥1).

CONCLUSIONS AND RELEVANCE

The findings of this population-based retrospective cohort study suggest that patients visiting the ED with first-episode syncope exhibit a subsequent crash risk no different than the average ED patient. More stringent driving restrictions after syncope may not be warranted.

Diagnostic approaches to syncope in Internal Medicine Departments and their effect on mortality

Most data on mortality and investigational approaches to syncope comes from patients presented to emergency departments (ED). The aim of this study is to report intermediate term mortality in syncope patients admitted to Internal Medicine Departments and whether different diagnostic approaches to syncope affect mortality. Methods and results A single-center retrospective-observational study conducted at the Tel Aviv "Sourasky" Medical Center. Data was collected from electronic medical records (EMRs), from January 2010 to December 2020. We identified 24,021 patients, using ICD-9-CM codes. Only 7967 syncope patients were admitted to Internal Medicine Departments and evaluated. Logistic regression models were used to determine the effects of diagnostic testing per patient in each department on 30-day mortality and readmission rates. All-cause 30-day mortality rate was 4.1%. There was a significant difference in the number of diagnostic tests performed per patient between the different departments, without affecting 30-day mortality. The 30-day readmission rate was 11.4%, of which 4.4% were a result of syncope. Conclusion Syncope patients admitted to Internal Medicine Departments show a 30-day all-cause mortality rate of ∼4%. Despite the heterogeneity in the approach to the diagnosis of syncope, mortality is not affected. This novel information about syncope patients in large Internal Medicine Departments is further proof that the diagnosis of syncope requires a logic, personalized approach that focuses on medical history and a few tailored, diagnostic tests.

Cardiac and Vascular Causes of Syncope and Atherosclerosis

PURPOSE OF REVIEW

Among the most common causes of cardiac syncope are arrhythmias and ischemic heart disease, both of which can coexist. The purpose of this review is to discuss the main causes of cardiac and vascular syncope related to atherosclerosis, its epidemiological and clinical aspects, warning signs, and initial approach.

RECENT FINDINGS

Cardiac syncope may have a frequency of up to 34% in elderly people. Atherosclerosis-related causes of cardiac and vascular syncope may be due to cardiac arrhythmia and/or structural impairment of the heart or arteries. Late ventricular tachycardia and late-onset high-grade atrioventricular block associated with myocardial ischemia may occur with syncope, which is related to higher mortality. Besides ventricular dysfunction, concentric remodeling is also a prognostic factor. In calcific degenerative aortic stenosis, syncope carries a worse prognosis than the other cardinal signs. Cardiac syncope has a high recurrence and mortality rate. There are red flag alerts that must be considered in risk stratification.

Psychological Aspects of Syncopes and Possible Association with Recurrency—The Role of Implantable Loop Recorders

Syncopes are a very common phenomenon and have a high recurrence rate. The differentiation between the psychogenic and physical, especially of arrhythmic origin, remains difficult. In many cases, an implantable loop recorder is used for the detection of possible arrhythmias, leading to syncopes. Yet, the existing literature suggests that psychological factors may play a significant role in recurrent syncopes. We aimed at analyzing the potential role of several psychological factors on the recurrence of arrhythmic or non-arrhythmic syncopes. Methods and results: A total of 119 patients, who had received an implantable loop recorder for recurrent syncopes at our center between 01/2018 and 12/2021, participated in this retrospective cohort study. Anxiety, depression and quality of life were assessed using extensively validated questionnaires (GAD-7, PHQ-9 and SF-12). The mean follow-up after loop recorder implantation was 710 ± 430 days and 50% of patients were female. The mean patient age was 54.8 ± 18.6 years. Most patients had no evidence of structural heart disease (84%), and normal LV function (92%). A statistical analysis revealed that the presence of structural heart disease was the strongest predictor for arrhythmic syncope during follow-up. In patients with non-arrhythmic syncopes, we found significantly higher levels of anxiety (GAD-7 score: 2.5 ± 2.6 vs. 4.8 ± 4.3) and depression (PHQ-9 score: 3.9 ± 3.6 vs. 6.8 ± 5.1), and a lower quality of life (SF-12 score: 33.7 ± 6.4 vs. 29.6 ± 7.8). Discussion: We identified factors as contributors to a better identification of patients at risk for arrhythmic as well as non-arrhythmic syncopes. Especially anxious or depressive symptoms may hinted at non-arrhythmic causes of syncope. However, the study was limited by its retrospective design and low patient number. Further trials should likewise combine the diagnostic yield of loop recorders with psychometric evaluations before implantation and combine it with additional diagnostic measures, such as video monitoring, to further examine the role of psychological factors in the pathomechanism and treatment of syncope.

McConnel sign, a simple highly specific sign for identification of a frequent, under diagnosed association: pulmonary embolism and syncope

Syncope is a common reason for emergency room visits and hospital admission and, in about one patient out of six it can be a manifestation of pulmonary embolism (PE). The prognosis of this condition is largely dependent on the timing of diagnosis and treatment since early anticoagulation may modify the clinical consequences of PE and further loss of consciousness. In this article, we describe the case of a woman presenting with syncope, who showed at the admission a cardiac ultrasound highly specific cluster of signs of pulmonary embolism. This rapid non-invasive evaluation permitted to identify causal diagnosis and to speed up the clinical process.

Syncope and the aging patient: Navigating the challenges

Syncope in the elderly patient is a common presentation and the most common causes are usually non-cardiac. Older adults however are more challenging dilemmas as their presentation is complicated by co-morbidities, mainly cardiovascular and neurodegenerative disorders. Frailty and cognitive impairment add to the ambiguity of the presentation, and polypharmacy is often a major modifiable contributing factor. Vasovagal syncope is a common presentation throughout life even as we age. It has a favorable prognosis and conservative management usually suffices. Vasovagal syncope in this population may be misdiagnosed as accidental falls and is frequently associated with injury, as is carotid sinus syndrome. The initial approach to these patients entails a detailed history and physical examination including a comprehensive medication history, orthostatic vital signs, and a 12-lead electrocardiogram. Further cardiac and neuroimaging rarely helps, unless directed by specific clinical findings. Head-up tilt testing and carotid sinus massage retain their diagnostic accuracy and safety in the elderly, and implantable loop recorders provide important information in many elderly patients with unexplained falls and syncope. The starting point in management of this population with non-cardiac syncope is attempting to withdraw unnecessary vasoactive and psychotropic medications. Non-pharmacologic and pharmacologic therapy for syncope in the elderly has limited efficacy and safety concerns. In selected patients, pacemaker therapy might offer symptomatic relief despite lack of efficacy when vasodepression is prominent. An approach focused on primary care with targeted specialist referral seems a safe and effective strategy.

Association of Occupational Distress and Low Sleep Quality with Syncope, Presyncope, and Falls in Workers

Syncope and presyncope episodes that occur during work could affect one's safety and impair occupational performance. Few data are available regarding the prevalence of these events among workers. The possible role of sleep quality, mental stress, and metabolic disorders in promoting syncope, presyncope, and falls in workers is unknown. In the present study, 741 workers (male 35.4%; mean age 47 ± 11 years), employed at different companies, underwent clinical evaluation and blood tests, and completed questionnaires to assess sleep quality, occupational distress, and mental disorders. The occurrence of syncope, presyncope, and unexplained falls during working life was assessed via an ad hoc interview. The prevalence of syncope, presyncope, and falls of unknown origin was 13.9%, 27.0%, and 10.3%, respectively. The occurrence of syncope was associated with an increased risk of occupational distress (adjusted odds ratio aOR: 1.62, confidence intervals at 95%: 1.05-2.52), low sleep quality (aOR: 1.79 CI 95%: 1.16-2.77), and poor mental health (aOR: 2.43 CI 95%: 1.52-3.87). Presyncope was strongly associated with occupational distress (aOR: 1.77 CI 95%: 1.25-2.49), low sleep quality (aOR: 2.95 CI 95%: 2.08-4.18), and poor mental health (aOR: 2.61 CI 95%: 1.78-3.84), while no significant relationship was found between syncope or presyncope and metabolic syndrome. These results suggest that occupational health promotion interventions aimed at improving sleep quality, reducing stressors, and increasing worker resilience might reduce syncope and presyncope events in the working population.

Prognostic Value of Biomarkers in Children and Adolescents With Orthostatic Intolerance

Orthostatic intolerance (OI) refers to a series of symptoms that occur during upright standing, which can be relieved when returned to the supine position. OI is a common cause of syncope in children and adolescents. In recent years, more and more studies have been carried out to assess the prognosis of OI by using biomarkers, among which, flow-mediated vasodilation, left ventricular ejection fraction and fractional shortening, hemodynamic change during head-up tilt test, detection of 24-h urinary sodium excretion, body mass index, midregional pro-adrenomedullin, and erythrocytic H2S producing rate are relatively stable, inexpensive, and easy to obtain. With the help of biomarkers, individualized treatment can be carried out to improve the long-term prognosis of children and adolescents with OI. This article reviews the prognostic value of biomarkers in children and adolescents with OI.

Syncope Time Frames for Adverse Events after Emergency Department Presentation: An Individual Patient Data Meta-Analysis

Background and Objectives: Knowledge of the incidence and time frames of the adverse events of patients presenting syncope at the ED is essential for developing effective management strategies. The aim of the present study was to perform a meta-analysis of the incidence and time frames of adverse events of syncope patients. Materials and Methods: We combined individual patients’ data from prospective observational studies including adult patients who presented syncope at the ED. We assessed the pooled rate of adverse events at 24 h, 72 h, 7–10 days, 1 month and 1 year after ED evaluation. Results: We included nine studies that enrolled 12,269 patients. The mean age varied between 53 and 73 years, with 42% to 57% females. The pooled rate of adverse events was 5.1% (95% CI 3.4% to 7.7%) at 24 h, 7.0% (95% CI 4.9% to 9.9%) at 72 h, 8.4% (95% CI 6.2% to 11.3%) at 7–10 days, 10.3% (95% CI 7.8% to 13.3%) at 1 month and 21.3% (95% CI 15.8% to 28.0%) at 1 year. The pooled death rate was 0.2% (95% CI 0.1% to 0.5%) at 24 h, 0.3% (95% CI 0.1% to 0.7%) at 72 h, 0.5% (95% CI 0.3% to 0.9%) at 7–10 days, 1% (95% CI 0.6% to 1.7%) at 1 month and 5.9% (95% CI 4.5% to 7.7%) at 1 year. The most common adverse event was arrhythmia, for which its rate was 3.1% (95% CI 2.0% to 4.9%) at 24 h, 4.8% (95% CI 3.5% to 6.7%) at 72 h, 5.8% (95% CI 4.2% to 7.9%) at 7–10 days, 6.9% (95% CI 5.3% to 9.1%) at 1 month and 9.9% (95% CI 5.5% to 17) at 1 year. Ventricular arrhythmia was rare. Conclusions: The risk of death or life-threatening adverse event is rare in patients presenting syncope at the ED. The most common adverse events are brady and supraventricular arrhythmias, which occur during the first 3 days. Prolonged ECG monitoring in the ED in a short stay unit with ECG monitoring facilities may, therefore, be beneficial.

Multicentre external validation of the Canadian Syncope Risk Score to predict adverse events and comparison with clinical judgement

BACKGROUND

The Canadian Syncope Risk Score (CSRS) has been proposed for syncope risk stratification in the emergency department (ED). The aim of this study is to perform an external multicenter validation of the CSRS and to compare it with clinical judgement.

METHODS

Using patients previously included in the SyMoNE database, we enrolled subjects older than 18 years who presented reporting syncope at the ED. For each patient, we estimated the CSRS and recorded the physician judgement on the patients' risk of adverse events. We performed a 30-day follow-up.

RESULTS

From 1 September 2015 to 28 February 2017, we enrolled 345 patients; the median age was 71 years (IQR 51-81), 174 (50%) were men and 29% were hospitalised. Serious adverse events occurred in 43 (12%) of the patients within 30 days. The area under the curve of the CSRS and clinical judgement was 0.75 (95% CI 0.68 to 0.81) and 0.68 (95% CI 0.61 to 0.74), respectively. The risk of adverse events of patients at low risk according to the CSRS and clinical judgement was 6.7% and 2%, with a sensitivity of 70% (95% CI 54% to 83%) and 95% (95% CI 84% to 99%), respectively.

CONCLUSION

This study represents the first validation analysis of CSRS outside Canada. The overall predictive accuracy of the CSRS is similar to the clinical judgement. However, patients at low risk according to clinical judgement had a lower incidence of adverse events as compared with patients at low risk according to the CSRS. Further studies showing that the adoption of the CSRS improve patients' outcomes is warranted before its widespread implementation.

A Rational Evaluation of the Syncope Patient: Optimizing the Emergency Department Visit

Syncope accounts for up to 2% of emergency department visits and results in the hospitalization of 12–86% of patients. There is often a low diagnostic yield, with up to 50% of hospitalized patients being discharged with no clear diagnosis. We will outline a structured approach to the syncope patient in the emergency department, highlighting the evidence supporting the role of clinical judgement and the initial electrocardiogram (ECG) in making the preliminary diagnosis and in safely identifying the patients at low risk of short- and long-term adverse events or admitting the patient if likely to benefit from urgent intervention. Clinical decision tools and additional testing may aid in further stratifying patients and may guide disposition. While hospital admission does not seem to offer additional mortality benefit, the efficient utilization of outpatient testing may provide similar diagnostic yield, preventing unnecessary hospitalizations.

Late diagnosed DiGeorge syndrome in a 44-year-old female: a rare cause for recurrent syncopes in adulthood-a case report

Background

DiGeorge syndrome, also known as ‘CATCH 22’, is the most common deletion in humans and is one of the velocardiofacial syndromes. It is characterized by a specific facial phenotype, and structural and functional abnormalities in the cardiac and endocrine systems. One form of endocrine system dysfunction is hypocalcaemia, which causes arrhythmic events and can result in a transient loss of consciousness. We present a case highlighting the late diagnosis of DiGeorge syndrome in a patient with recurrent episodes of syncope due to suspected arrhythmic events secondary to hypocalcaemia.

Case summary

A 44-year-old woman was referred for further investigation of recurrent syncope episodes and documented transient QT-prolongation with hypocalcaemia. Previous detailed cardiological examination, including invasive procedures such as coronary angiography and cardiac magnetic resonance tomography, was unremarkable. Slight characteristic facial dysmorphia and transient hypocalcaemia were strongly suggestive of DiGeorge syndrome. The diagnosis was confirmed by genetic testing. Calcium substitution was initiated and no recurrent episodes of syncope or arrhythmic events were reported during 12 months of follow-up.

Discussion

Clinical presentation and time of manifestation of the DiGeorge syndrome varies widely depending on the mutation expression extent. An atypical disease course may delay the diagnosis and appropriate management of affected patients. In this case, confirmation of the diagnosis allowed the initiation of appropriate treatment, reducing the risk for further events. Given that syncope and arrhythmia can be the first and only manifestation of late-onset DiGeorge syndrome, specialists in adult cardiology need to be aware of this presentation.

Machine Learning and Syncope Management in the ED: The Future Is Coming

In recent years, machine learning (ML) has been promisingly applied in many fields of clinical medicine, both for diagnosis and prognosis prediction. Aims of this narrative review were to summarize the basic concepts of ML applied to clinical medicine and explore its main applications in the emergency department (ED) setting, with a particular focus on syncope management. Through an extensive literature search in PubMed and Embase, we found increasing evidence suggesting that the use of ML algorithms can improve ED triage, diagnosis, and risk stratification of many diseases. However, the lacks of external validation and reliable diagnostic standards currently limit their implementation in clinical practice. Syncope represents a challenging problem for the emergency physician both because its diagnosis is not supported by specific tests and the available prognostic tools proved to be inefficient. ML algorithms have the potential to overcome these limitations and, in the future, they could support the clinician in managing syncope patients more efficiently. However, at present only few studies have addressed this issue, albeit with encouraging results.

Incidence, characteristics, determinants, and prognostic impact of recurrent syncope

AIMS

The aim of this study is to characterize recurrent syncope, including sex-specific aspects, and its impact on death and major adverse cardiovascular events (MACE).

METHODS AND RESULTS

We characterized recurrent syncope in a large international multicentre study, enrolling patients ≥40 years presenting to the emergency department (ED) with a syncopal event within the last 12 h. Syncope aetiology was centrally adjudicated by two independent cardiologists using all information becoming available during syncope work-up and long-term follow-up. Overall, 1790 patients were eligible for this analysis. Incidence of recurrent syncope was 20% [95% confidence interval (CI) 18-22%] within the first 24 months. Patients with an adjudicated final diagnosis of cardiac syncope (hazard ratio (HR) 1.50, 95% CI 1.11-2.01) or syncope with an unknown aetiology even after central adjudication (HR 2.11, 95% CI 1.54-2.89) had an increased risk for syncope recurrence. Least Absolute Shrinkage and Selection Operator regression fit on all patient information available early in the ED identified >3 previous episodes of syncope as the only independent predictor for recurrent syncope (HR 2.13, 95% CI 1.64-2.75). Recurrent syncope carried an increased risk for death (HR 1.87, 95% CI 1.26-2.77) and MACE (HR 2.69, 95% CI 2.02-3.59) over 24 months of follow-up, however, with a time-dependent effect. These findings were confirmed in a sensitivity analysis excluding patients with syncope recurrence or MACE before or during ED evaluation.

CONCLUSION

Recurrence rates of syncope are substantial and vary depending on syncope aetiology. Importantly, recurrent syncope carries a time-dependent increased risk for death and MACE.

TRIAL REGISTRATION

BAsel Syncope EvaLuation (BASEL IX, ClinicalTrials.gov registry number NCT01548352).

Lack of benefit from hospitalization in patients with syncope: A propensity analysis

STUDY OBJECTIVE

Patients with syncope are frequently admitted to the hospital, but whether this improves outcome is unknown. We tested whether hospitalization reduced mortality in patients who presented to emergency departments (EDs) with syncope.

METHODS

We conducted a propensity analysis of the outcomes of patients ≥18 years old presenting to EDs with a primary diagnosis of syncope in April 2004-March 2013. The model used 1:1 nearest-neighbor matching to predicted admission using age, sex, urban residence, household income, and 14 significant comorbidities from 4 administrative databases of the province of Alberta. The primary outcome was death.

RESULTS

There were 57,417 ED patients with a primary diagnosis of syncope; 8864 were admitted, and 48,553 were discharged in <24 hours. Admitted patients were older (median 76 vs 49 years), male (53% vs 45%), rural (23% vs 18%), and had lower income (median $58,599 vs $61,422); all P < 0.001. All comorbidities were higher in admitted patients (mean Charlson scores, 1.9 vs 0.7; P < 0.001). The propensity-matched hospitalized patients had higher 30-day mortality (3.5% vs 1.0%) and 1-year mortality (14.1% vs 8.6%); both P < 0.001. Mortality in all propensity quintiles was higher in the hospitalized group (all P < 0.001). The most common causes of death in 2719 patients included chronic ischemic heart disease, 14%; lung cancer, 7.1%; acute myocardial infarction, 6.9%; stroke, 3.7%; chronic obstructive pulmonary disease, 3.6%; dementia, 2.6%; and heart failure, 2.5%.

CONCLUSIONS

Hospital admission did not reduce early or late mortality in patients who presented to the ED with syncope. Mortality is associated with comorbidities.

Predictive Accuracy of Electrocardiographic Monitoring of Patients With Syncope in the Emergency Department: The SyMoNE Multicenter Study

BACKGROUND

Arrhythmia is one of the most worrisome causes of syncope. Electrocardiographic (ECG) monitoring is crucial for the management of non-low-risk patients in the emergency department (ED). However, its diagnostic accuracy and optimal duration are unknown. We aimed to assess the diagnostic accuracy of ECG monitoring in non-low-risk patients with syncope in the ED.

METHODS

This prospective multicenter observational study included adult patients presenting to the ED after syncope. Patients without an obvious etiology after ED evaluation who were classified by ED physicians as being at non-low risk of adverse events underwent ECG monitoring. We assessed sensitivity, specificity, and diagnostic yield (defined as the proportion of patients with true-positive ECG monitoring findings) of ECG monitoring in the identification of 7- and 30-day adverse and arrhythmic events according to monitoring duration.

RESULTS

Of 242 patients included in the study, 29 patients had 7-day serious outcomes. Ten additional patients had serious outcomes at 30 days. The overall sensitivity, specificity, and diagnostic yield of ECG monitoring in the identification of 7-day adverse events were 0.55 (95% confidence interval [CI] = 0.36 to 0.74], 0.93 (95% CI = 0.89 to 0.96), and 0.07 (95% CI = 0.04 to 0.10), respectively. The sensitivity, specificity, and diagnostic yield of >12-hour ECG monitoring in the identification of 7-day adverse events were 0.89 (95% CI = 0.65 to 0.99), 0.78 (95% CI = 0.67 to 0.87), and 0.18 (95% CI = 0.12 to 0.28), respectively. Similar results were observed for 30-day adverse events. The median (interquartile range) ECG monitoring time was 6.5 (6 to 15) hours. ECG monitoring findings were positive in 31 patients.

CONCLUSIONS

Although the overall diagnostic accuracy of ECG monitoring is fair, its sensitivity at >12 hours' duration is substantially higher. These results suggest that prolonged (>12 hours) monitoring is a safe alternative to hospital admission in the management of non-low-risk patients with syncope in the ED.

[Features of changes in volume-impedance hemodynamic indicators during the tilt test in young males with a history of vasovagal syncopes]

BACKGROUND

The direction of changes in hemodynamic parameters during the tilt test (TT) nin individuals with history of vasovagal syncope (VVS) is a subject of discussion.

OBJECTIVE

to study changes of volume-impedance hemodynamic indicators in the process of tilt test in somatically healthy young men with history of VVS.

MATERIALS AND METHODS

A total of 102 men aged 18-30 years were divided into 4 groups, taking into account the specific features of fainting history and response to TT. Persons of group 1 (n=14) had history of VVS and positive response to TT (syncope). Subjects of group 2 (n=14) had history of VVS and a pattern of postural tachycardia without fainting during TT. Persons of group 3 (n=42) had history of VVS and negative response to TT. Subjects of group 4 (n=32) had no history of VVS and negative response to TT. During TT, we studied dynamics of some indicators, including cardiac output (CO) and total peripheral vascular resistance (TPVR).

RESULTS

In individuals of all groups in the initial horizontal phase of TT values of CO and TPVR corresponded to the norm. Subjects of group 1 had significantly lower CO compared with subjects of groups 2, 3, 4 (p&lt;0.05, p&lt;0.01, p&lt;0.05, respectively). Values of TPVR in subjects of group 1 were significantly higher than in subjects of groups 2, 3, 4 (p&lt;0.05; p&lt;0.05; p&lt;0.05, respectively). In response to orthostasis CO values increased in groups 1, 2, 4 (by 18%, 10%, 5%, respectively) and did not change in group 3; TPVR values decreased in groups 1, 2 (by 8%, 0.5%, respectively), and increased in groups 3, 4 (by 8%, 4% respectively). In the final horizontal phase of TT, CO values in group 1 were significantly lower than in groups 3, 4 (p&lt;0.05), while TPVR values did not significantly differ between all groups (p&gt;0.05).

CONCLUSIONS

In tilt-positive and tilt-negative subjects with history of VVS, standardized postural stress leads to unidirectional changes in cardiac output, but to multidirectional changes in total peripheral vascular resistance.

Syncope in the Emergency Department

Syncope is a common presentation to Emergency Departments (EDs). Estimates on the frequency of visits (0.6–1.7%) and subsequent rates of hospitalizations (12–85%) vary according to country. The initial ED evaluation for syncope consists of a detailed history, physical examination and 12-lead electrocardiogram (ECG). The use of additional diagnostic testing and specialist evaluation should be based on this initial evaluation rather than an unstructured approach of broad-based testing. Risk stratification performed in the ED is important for estimating prognosis, triage decisions and to establish urgency of any further work-up. The primary approach to risk stratification focuses on identifying high- and low-risk predictors. The use of prediction tools may be used to aid in physician decision-making; however, they have not performed better than the clinical judgment of emergency room physicians. Following risk stratification, decision for hospitalization should be based on the seriousness of the underlying cause for syncope or based on high-risk features, or the severity of co-morbidities. For those deemed intermediate risk, access to specialist assessment and related testing may occur in a syncope unit in the emergency department, as an outpatient, or in a less formal care pathway and is highly dependent on the local healthcare system. For syncope patients presenting to the ED, ~0.8% die and 10.3% suffer a non-fatal severe outcome within 30 days.

[Differential diagnostics of unclear syncope]

The clarification of syncope is a diagnostic challenge as possible causes often occur only intermittently. Therefore, a detailed and standardized anamnesis is essential as it 1) differentiates syncope from other transient losses of consciousness (TLOC) and 2) directly clarifies possible causes of syncope. The risk stratification plays a central and very important role in order to avoid unnecessary examinations in patients with benign syncope and to provide patients with life-threatening, mostly cardiac syncopal episodes with timely diagnostics and treatment. In cases where the cause of syncope is still unclear, a standardized approach is indicated using extended diagnostics, such as a tilt table examination, a carotid sinus pressure test, prolonged telemetric monitoring or clarification with an implantable loop recorder (ILR).

Long-term outcomes in syncope patients presenting to the emergency department: A systematic review

INTRODUCTION

Long-term outcomes among syncope patients are not well studied to guide physicians regarding outpatient testing and follow-up. The objective of this study was to conduct a systematic review for outcomes at 1-year or later among ED syncope patients.

METHODS

We searched Cochrane Central, Medline, Medline in Process, PubMed, Embase, and the Cumulative Index to Nursing databases from inception to December 2018. We included studies that reported long-term outcomes among ED syncope patients. We excluded studies on patients <16 years old, studies that included syncope mimickers (pre-syncope, seizure, intoxication, loss of consciousness after head trauma), case reports, letters to the editor, non-English and review articles. Outcomes included death, syncope recurrence requiring hospitalization, arrhythmias and procedural interventions for arrhythmias. Meta-analysis was performed by pooling the outcomes using random effects model.

RESULTS

Initial literature search generated 2,094 articles duplicate removal. Of the 50 articles selected for full-text review, 19 articles with 98,211 patients were included in this review: of which 12 were included in the 1-year outcome meta-analysis. Pooled analysis showed : 7.0% mortality; 16.0% syncope recurrence requiring hospitalization; 6.0% with device insertion. 1-year arrhythmias reported in two studies were 1.1 and 26.4%. Pooled analysis for outcome at 31 to 365 days showed: 5.0% mortality and 1% device insertion. Two studies reported 4.9% and 21% mortality at 30 months and 4.2 years follow-up.

CONCLUSIONS

An important proportion of ED syncope patients suffer long-term morbidity and mortality. Appropriate follow-up is needed and future research to identify patients at risk is needed.

Syncope in a Working-Age Population: Recurrence Risk and Related Risk Factors

Syncope in a worker undertaking risky tasks may result in fatalities for the individual or for third parties. We aimed at assessing the rate of syncope recurrence and the risk factors underlying the likelihood of syncope relapse in a working-age population. A prospective cohort of all patients aged 18–65 years consecutively admitted to the Emergency Department for syncope was enrolled. Risk of syncope relapse was assessed at a six-month, 1-year, and 5-year follow-up. Predictors of syncope recurrence have been evaluated at six months and 1 year from the syncope index by a multivariable logistic regression analysis. 348 patients were enrolled. Risk of syncope relapse was 9.2% at 6 months, 11.8% at 1 year, and 23.4% at 5 years. At 6-month follow-up, predictor of syncope recurrence was ≥3 prior lifetime syncope episodes. At 1-year, ≥3 prior lifetime syncope episodes, diabetes mellitus, and anaemia were risk factors for syncope relapse. There was an exceeding risk of recurrence in the first 6 months and a reduced risk of 3.5% per year after the first year. Anaemia, diabetes mellitus, and prior lifetime syncope burden are of importance when giving advice about the resumption of “high risk” jobs following a syncope episode.

Prevalence of Pulmonary Embolism Among Emergency Department Patients With Syncope: A Multicenter Prospective Cohort Study

STUDY OBJECTIVE

The prevalence of pulmonary embolism among patients with syncope is understudied. In accordance with a recent study with an exceptionally high pulmonary embolism prevalence, some advocate evaluating all syncope patients for pulmonary embolism, including those with another clear cause for their syncope. We seek to evaluate the pulmonary embolism prevalence among emergency department (ED) patients with syncope.

METHODS

We combined data from 2 large prospective studies enrolling adults with syncope from 17 EDs in Canada and the United States. Each study collected the results of pulmonary embolism-related investigations (ie, D-dimer, ventilation-perfusion scan, or computed tomography [CT] pulmonary angiography) and 30-day adjudicated outcomes: pulmonary embolism or nonpulmonary embolism outcome (arrhythmia, myocardial infarction, serious hemorrhage, and death).

RESULTS

Of the 9,374 patients enrolled, 9,091 (97.0%; median age 66 years, 51.9% women) with 30-day follow-up were analyzed: 547 (6.0%) were evaluated for pulmonary embolism (278 [3.1%] had D-dimer, 39 [0.4%] had ventilation-perfusion scan, and 347 [3.8%] had CT pulmonary angiography). Overall, 874 patients (9.6%) experienced 30-day serious outcomes: 818 patients (9.0%) with nonpulmonary embolism serious outcomes and 56 (prevalence 0.6%; 95% confidence interval 0.5% to 0.8%) with pulmonary embolism (including 8 [0.2%] out of 3521 patients diagnosed during the index hospitalization and 7 [0.1%] diagnosed after the index visit). Eighty-six patients (0.9%) died, and 4 deaths (0.04%) were related to pulmonary embolism. Only 11 patients (0.1%) with a nonpulmonary embolism serious condition had a concomitant pulmonary embolism.

CONCLUSION

The prevalence of pulmonary embolism is very low among ED patients with syncope, including those hospitalized after syncope. Although an underlying pulmonary embolism may cause syncope, clinicians should be cautious about indiscriminate investigations for pulmonary embolism.

Trends in use of echocardiography in hospitalized patients with syncope

PURPOSE

We sought to assess the trends in use, predictors of echocardiography, and its impact on in-hospital mortality in patients admitted with syncope using a large national database.

METHODS

Utilizing the Nationwide Inpatient Sample (NIS) database from 2001 to 2014, we identified adult patients (>18 years) with a primary discharge diagnosis of syncope and use of echocardiogram was ascertained.

RESULTS

A total of 3 174 619 patients with a primary discharge diagnosis of syncope were identified, of which 184 167 (5.8%) underwent an echocardiogram. The rate of syncope hospitalization remained constant between 2001 and 2009 (1.1/1000 US population) but has since decreased steadily to about 0.5/1000 US population in 2014. After adjusting for patient and hospital characteristics, the rate of echocardiogram use increased significantly from 5.1% in 2001 to 6.8% in 2014 (2.7% relative increase per year [P_trend  = 0.024]). Predictors of use were cardiac disorders, hypertension, diabetes, peripheral vascular disease, and renal failure. After adjusting for baseline risk, use of echocardiography was not associated with in-hospital mortality (OR = 0.827, P = 0.155), but was associated with a 14.6% increase in adjusted length of stay and a 22.6% increase in adjusted hospital cost compared to no echocardiography use (both P < 0.001).

CONCLUSIONS

The admission rates for syncope are decreasing and use of echocardiography in hospitalized patients with syncope is appropriately low. Given the lack of any favorable impact on mortality and the association with increased costs, there is a continued need to emphasize evidence-based use of echocardiography in patients presenting with syncope.

[Transient loss of consciousness : Algorithm for the (differential) diagnosis of syncope at emergency department]

Transient loss of consciousness (TLoC) is a common complaint leading to presentation at the emergency department. This comprises a heterogeneous group of disorders including cerebral events, metabolic disturbances, intoxication, psychogenic patterns or any form of syncope. While many causes are benign and self-limited not requiring extensive in-hospital evaluation, others are potentially severe. The optimal evaluation of patients with TLoC/syncope follows a risk-adapted diagnostic algorithm in order to exclude life-threatening conditions and to identify those with high risk for further deterioration like structural heart diseases requiring further diagnostic evaluation. Low-risk patients can be discharged without further extensive diagnostic work up. This article presents an algorithm for structured, evidence-based care of the syncope patient in accordance with the recently launched "2018 ESC guidelines for the diagnosis and management of syncope" in order to ensure that patients requiring hospitalization are managed appropriately and those with benign causes are discharged safely. The English version of this algorithm is available at the end of the article under "Supplementary Material".

Prognostic significance of noncardiac syncope in the general population: A systematic review and meta-analysis

INTRODUCTION

Cardiac syncope heralds significantly higher mortality compared with syncope due to noncardiac causes or unknown etiology, commonly considered a benign event. A few epidemiologic studies have examined the outcome of noncardiac/unexplained syncope comparing individuals with and without syncope, but with controversial results. We performed a systematic review and meta-analysis to clarify whether history of noncardiac/unexplained syncope is associated with increased all-cause mortality in the general population.

METHODS AND RESULTS

Our systematic review of the literature published between January 1, 1966, and March 31, 2018 sought prospective, observational, cohort studies reporting summary-level outcome data about all-cause mortality in subjects with history of noncardiac/unexplained syncope compared with syncope-free participants. Adjusted hazard ratios were pooled through inverse variance random-effect meta-analysis to compute the summary effect size. Meta-regression models were performed to explore the effect of age, cardiovascular risk factors, or other potential confounders on the measured effect size. We identified four studies including 287 382 individuals (51.6% men; age, 64 ± 12 years): 38 843 with history of noncardiac/unexplained syncope and 248 539 without history of syncope. The average follow-up was 4.4 years. History of noncardiac/unexplained syncope was associated with higher all-cause mortality (pooled adjusted hazard ratio = 1.13; 95% confidence interval, 1.05 to 1.23). Meta-regression analysis showed a stronger positive relationship proportional to aging and increasing prevalence of diabetes and hypertension.

CONCLUSIONS

This study-level meta-analysis showed that among older, diabetic and/or hypertensive individuals, history of noncardiac/unexplained syncope, even in the absence of an obvious cardiac etiology, is associated with higher all-cause mortality.

[Syncope in prehospital emergency medicine]

Loss of consciousness is a frequent cause for an emergency call to the emergency medical services (EMS). It can be associated with life-threatening conditions. A distinction must be made between transient loss of consciousness (TLOC) and syncope, which is of cardiovascular origin by definition. Initial assessment in prehospital emergency care should follow the ABCDE algorithm including a 12-lead ECG. The presence of important risk factors such as occurrence in supine position, physical stress, palpitations, history of heart diseases, and any abnormalities in the ECG warrants hospital admission. Initial treatment without admission to an emergency department may only be acceptable for healthy patients without any risk factors and injuries, when vital signs are normal and an orthostatic etiology seems most likely.

Neural networks as a tool to predict syncope risk in the Emergency Department

Aims

There is no universally accepted tool for the risk stratification of syncope patients in the Emergency Department. The aim of this study was to investigate the short-term predictive accuracy of an artificial neural network (ANN) in stratifying the risk in this patient group.

Methods and results

We analysed individual level data from three prospective studies, with a cumulative sample size of 1844 subjects. Each dataset was reanalysed to reduce the heterogeneity among studies defining abnormal electrocardiogram (ECG) and serious outcomes according to a previous consensus. Ten variables from patient history, ECG, and the circumstances of syncope were used to train and test the neural network. Given the exploratory nature of this work, we adopted two approaches to train and validate the tool. One approach used 4/5 of the data for the training set and 1/5 for the validation set, and the other approach used 9/10 for the training set and 1/10 for the validation set. The sensitivity, specificity, and area under the receiver operating characteristic curve of ANNs in identifying short-term adverse events after syncope were 95% [95% confidence interval (CI) 80-98%], 67% (95% CI 62-72%), 0.69 with the 1/5 approach and 100% (95% CI 84-100%), 79% (95% CI 72-85%), 0.78 with the 1/10 approach.

Conclusion

The results of our study suggest that ANNs are effective in predicting the short-term risk of patients with syncope. Prospective studies are needed in order to compare ANNs' predictive capability with existing rules and clinical judgment.

Outcomes in syncope research: a systematic review and critical appraisal

Syncope is the common clinical manifestation of different diseases, and this makes it difficult to define what outcomes should be considered in prognostic studies. The aim of this study is to critically analyze the outcomes considered in syncope studies through systematic review and expert consensus. We performed a systematic review of the literature to identify prospective studies enrolling consecutive patients presenting to the Emergency Department with syncope, with data on the characteristics and incidence of short-term outcomes. Then, the strengths and weaknesses of each outcome were discussed by international syncope experts to provide practical advice to improve future selection and assessment. 31 studies met our inclusion criteria. There is a high heterogeneity in both outcome choice and incidence between the included studies. The most commonly considered 7-day outcomes are mortality, dysrhythmias, myocardial infarction, stroke, and rehospitalisation. The most commonly considered 30-day outcomes are mortality, haemorrhage requiring blood transfusion, dysrhythmias, myocardial infarction, pacemaker or implantable defibrillator implantation, stroke, pulmonary embolism, and syncope relapse. We present a critical analysis of the pros and cons of the commonly considered outcomes, and provide possible solutions to improve their choice in ED syncope studies. We also support global initiatives to promote the standardization of patient management and data collection.

Trends of hospitalizations for syncope/collapse in the United States from 2004 to 2013-An analysis of national inpatient sample

INTRODUCTION

Syncope/collapse is a common reason for emergency department visits, and approximately 30-40% of these individuals are hospitalized. We examined changes in hospitalization rates, in-hospital mortality, and cost of syncope/collapse-related hospital care in the United States from 2004 to 2013.

METHODS

We used the US Nationwide Inpatient Sample (NIS) from 2004 to 2013 to identify syncope/collapse-related hospitalizations using ICD-9, code 780.2, as the principal discharge diagnosis. Data are presented as mean ± SEM.

RESULTS

From 2004 to 2013, there was a 42% reduction in hospitalizations with a principal discharge diagnosis of syncope/collapse from 54,259 (national estimate 253,591) in 2004 to 31,427 (national estimate 156,820) in 2013 (P < 0.0001). The mean length of hospital stays decreased (2.88 ± 0.04 days in 2004 vs. 2.54 ± 0.02 in 2013; P < 0.0001), while in-hospital mortality did not change (0.28% in 2004 vs. 0.18% in 2013; P  =  0.12). However, mean charges (inflation adjusted) for syncope/collapse-related hospitalization increased by 43.6% from $17,514 in 2004 to $25,160 in 2013 (P < 0.0001). The rates of implantation of permanent pacemakers and implantable cardioverter defibrillator remained low during these hospitalizations, and decreased over time (P for both < 0.0001).

CONCLUSIONS

Hospitalization rates for syncope/collapse have decreased significantly in the US from 2004 to 2013. Despite a modest reduction in length of stay, the cost of syncope/collapse-related hospital care has increased.

The incidence of acute pulmonary embolism following syncope in anticoagulant-naïve patients: A retrospective cohort study

BACKGROUND

A recently published, large prospective study showed unexpectedly high prevalence of acute pulmonary embolism (APE) among patients hospitalized for syncope. In such a case, a high incidence of recurrent pulmonary embolism is expected among patients who were discharged without APE workup.

OBJECTIVES

To determine the incidence of symptomatic APE among patients hospitalized for a first episode of syncope and discharged without APE workup or anticoagulation.

METHODS

This retrospective cohort study included patients hospitalized at Rambam Health Care Campus between January 2006 and February 2017 with a primary admission diagnosis of syncope, who were not investigated for APE and were not taking anticoagulants. The patients were followed up for up to three years after discharge. The occurrence of venous thromboembolism (VTE) during the follow-up period was documented.

RESULTS

The median follow-up duration was 33 months. 1,126 subjects completed a three-year follow-up. During this period, 38 patients (3.38%) developed VTE, 17 (1.51%) of them had APE. The cumulative incidence of VTE and APE was 1.9% (95% CI 1.3%-2.5%) and 0.9% (95% CI 0.4%-1.3%) respectively. Only seven subjects developed APE during the first year of follow-up. The median times from the event of syncope to the development of APE and VTE were 18 and 19 months respectively.

CONCLUSIONS

The cumulative incidence of VTE during a three-year follow-up period after an episode of syncope is low. In the absence of clinical suspicion, a routine diagnostic workup for APE in patients with syncope cannot be recommended.

Implantable loop recorders in patients with unexplained syncope: Clinical predictors of pacemaker implantation

BACKGROUND

Implantable loop recorders (ILR) are a valuable tool for the investigation of unexplainedsyncopal episodes. The aim of this retrospective single center study was to identify predictive factors for pacemaker implantation in patients with unexplained syncope who underwent ILR insertion.

METHODS

One hundred six patients were retrospectively analyzed (mean age 59.1 years; 47.2% male) with unexplained syncope and negative conventional testing who underwent ILR implantation. The pri- mary study endpoint was detection of symptomatic or asymptomatic bradycardia requiring pacemaker implantation.

RESULTS

The average follow-up period after ILR implantation was 20 ± 15 months. Pacemaker im- plantation according to current guidelines was necessary in 22 (20.8%) patients, mean duration until index bradycardia was 81 ± 88 (2-350) days. Ten (45.5%) patients received a pacemaker due to sinus arrest, 7 (31.8%) patients due to third-degree atrioventricular block, 2 (9.1%) patients due to second- degree atrioventricular block and 1 (4.5%) patient due to atrial fibrillation with a slow ventricular rate. Three factors remained significant in multivariate analysis: obesity, which defined by a body mass index above 30 kg/m2 (OR: 7.39, p = 0.014), a right bundle branch block (OR: 9.40, p = 0.023) and chronic renal failure as defined by a glomerular filtration rate of less than 60 mL/min (OR: 6.42, p = 0.035).

CONCLUSIONS

Bradycardia is a frequent finding in patients undergoing ILR implantation due to un- explained syncope. Obesity, right bundle branch block and chronic renal failure are independent clinical predictors of pacemaker implantation.

Autonomic Dysfunction in Cardiology: Pathophysiology, Investigation, and Management

Presyncope and syncope are common medical findings, with a > 40% estimated lifetime prevalence. These conditions are often elicited by postural stress and can be recurrent and accompanied by debilitating symptoms of cerebral hypoperfusion. Therefore, it is critical for physicians to become familiar with the diagnosis and treatment of common underlying causes of presyncope and syncope. In some patients, altered postural hemodynamic responses result from a failure of compensatory autonomic nervous system reflex mechanisms. The most common presentations of presyncope and syncope secondary to this autonomic dysfunction include vasovagal syncope, neurogenic orthostatic hypotension, and postural tachycardia syndrome. The most sensitive method for diagnosis is a detailed initial evaluation with medical history, physical examination, and resting electrocardiogram to rule out cardiac syncope. Physical examination should include measurement of supine and standing blood pressure and heart rate to identify the pattern of hemodynamic regulation during orthostatic stress. Additional testing may be required in patients without a clear diagnosis after the initial evaluation. Management of patients should focus on improving symptoms and functional status and not targeting arbitrary hemodynamic values. An individualized structured and stepwise approach should be taken for treatment, starting with patient education, lifestyle modifications, and use of physical counter-pressure manoeuvres and devices to improve venous return. Pharmacologic interventions should be added only when conservative approaches are insufficient to improve symptoms. There are no gold standard approaches for pharmacologic treatment in these conditions, with medications often used off label and with limited long-term data for effectiveness.

A Population-Based Cohort Study Evaluating Outcomes and Costs for Syncope Presentations to the Emergency Department

OBJECTIVES

This study sought to examine outcomes and costs of patients with syncope admitted and discharged from the emergency department (ED).

BACKGROUND

ED visits for syncope are common, yet the impact on health care utilization is relatively unknown.

METHODS

A total of 51,831 consecutive patients presented to the ED with a primary diagnosis of syncope (International Classification of Diseases-9 code 780.2 and International Classification of Diseases-10 code R55) in Alberta, Canada from 2006 to 2014. Outcomes included 30-day syncope ED and hospital readmissions; 30-day and 1-year mortality; and annual inpatient, outpatient, physician, and drug costs, cumulative.

RESULTS

Of adults presenting to the ED, 6.6% were hospitalized and discharged with a primary diagnosis of syncope (Cohort 1), 8.7% were hospitalized and discharged with a primary diagnosis other than syncope (Cohort 2), and 84.7% were discharged home with a syncope diagnosis (Cohort 3). The 30-day ED revisits for syncope varied from 1.2% (Cohort 2) to 2.4% (Cohort 1) (p < 0.001), and readmission rates were <1% among cohorts. Short- and long-term mortality rates were highest for Cohort 2 and lowest for Cohort 3 (30-day mortality: Cohort 1 of 1.2%, Cohort 2 of 5.2%, Cohort 3 of 0.4%; p < 0.001) (1-year mortality: Cohort 1 of 9.2%, Cohort 2 of 17.7%, Cohort 3 of 3.0%; p < 0.001). Total cost of syncope presentations was $530.6 million (Cohort 1: $75.3 million; $29,519/patient, Cohort 2: $138.1 million; $42,042/patient, Cohort 3: $317.3 million; $9,963/patient; p<0.001).

CONCLUSIONS

Most patients with syncope presenting to the ED were discharged and had a favorable prognosis but overall costs were high compared with patients hospitalized. Further research is needed for cost-saving strategies across all cohorts.

Cardiovascular risk after hospitalisation for unexplained syncope and orthostatic hypotension

Objective

To investigate the relationship of hospital admissions due to unexplained syncope and orthostatic hypotension (OH) with subsequent cardiovascular events and mortality.

Methods

We analysed a population-based prospective cohort of 30 528 middle-aged individuals (age 58±8 years; males, 40%). Adjusted Cox regression models were applied to assess the impact of unexplained syncope/OH hospitalisations on cardiovascular events and mortality, excluding subjects with prevalent cardiovascular disease.

Results

After a median follow-up of 15±4 years, 524 (1.7%) and 504 (1.7%) participants were hospitalised for syncope or OH, respectively, yielding 1.2 hospital admissions per 1000 person-years for each diagnosis. Syncope hospitalisations increased with age (HR, per 1 year: 1.07, 95% CI 1.05 to 1.09), higher systolic blood pressure (HR, per 10 mm Hg: 1.06, 95% CI 1.01 to 1.12), antihypertensive treatment (HR: 1.26, 95% CI 1.00 to 1.59), use of diuretics (HR: 1.77, 95% CI 1.31 to 2.38) and prevalent cardiovascular disease (HR: 1.59, 95% CI 1.14 to 2.23), whereas OH hospitalisations increased with age (HR: 1.11, 95% CI 1.08 to 1.12) and prevalent diabetes (HR: 1.82, 95% CI 1.23 to 2.70). After exclusion of 1399 patients with prevalent cardiovascular disease, a total of 473/464 patients were hospitalised for unexplained syncope/OH before any cardiovascular event. Hospitalisation for unexplained syncope predicted coronary events (HR: 1.85, 95% CI 1.49 to 2.30), heart failure (HR: 2.24, 95% CI 1.65 to 3.04), atrial fibrillation (HR: 1.84, 95% CI 1.50 to 2.26), aortic valve stenosis (HR: 2.06, 95% CI 1.28 to 3.32), all-cause mortality (HR: 1.22, 95% CI 1.09 to 1.37) and cardiovascular death (HR: 1.72, 95% CI 1.23 to 2.42). OH-hospitalisation predicted stroke (HR: 1.66, 95% CI 1.24 to 2.23), heart failure (HR: 1.78, 95% CI 1.21 to 2.62), atrial fibrillation (HR: 1.89, 95% CI 1.48 to 2.41) and all-cause mortality (HR: 1.14, 95% CI 1.01 to 1.30).

Conclusions

Patients discharged with the diagnosis of unexplained syncope or OH show higher incidence of cardiovascular disease and mortality with only partial overlap between these two conditions.